Can't figure out how to do it! After several hours of frustration I got the UHS Hints and three walkthroughs. It was impossible to do what they said to do ... Gravin won't talk until after the furnace is fixed. After it is fixed he tells me to see the Cyber-technition, but that guy won't say anything about upgrading and I can't ask him about it. I haven't found any new rooms that I can get into without the upgrade. ARGHHHHHHHH!! I'm about ready to check into that asylum myself! LOL!

I had the same problem.. Here's the way I got through it: After you have fixed the furnace, talk to the Cyber-technition first. You should then have the dialog option to talk about the upgrade. After that go talk to Gravin.

You have to try to get into the Royal Chamber before you can upgrade your clearance. It's the building just to the North of the Cyber-Technician.

Try to get into Royal Chamber, Talk to Technician, Talk to Cravin, Go back to Technician again.

You need:
- Gavin authorization: you'll get this one by finding out what happened with his scientific crew,
- Insectoid's arm: this one you'll find on the ground after causing a small accident in the boiler room.